So I've been thinking, it seems that nearly everybody with EFI has serious
tuning issues which makes a carb sound more and more attractive.  I know
Paul has drawn a Holley setup on the website and an off the shelf leaning
solution id available but the Weber DCOE just
packages soooo much nicer on the rotary, especially with P ports.   We
already know it runs well and makes tons of power on the dyno so the only
problem is a workable leaning system for cruise.  I had the thought, instead
of trying to alter the fuel flow why not alter the air flow?  Why not
install taps into the runners (or the housings) teed to a cable operated
ball valve which bypasses the carb;  basically a controlled vacuum leak.
When the ball valve is opened it would allow filtered air to bypass the carb
reducing the signal to the venturis and causing less fuel to be drawn.
Sizing would probably take some trial and error but once sorted it should be
dead nuts reliable.  Is there any reason this wouldn't work?  What am I
missing? Everett Rankin

Nothing. You are right on. A Holley 350 CFM 2 barrel is much easier to lean
with off the shelf parts and about 25% of the price of a $1000 Weber.

Combine it with an outboard type ignition system/alternator  and you get a
very reliable, low cost  and simple aircraft engine.

Paul Lamar



Paul,
These Adjust-a-Jets require putting a flathead screwdriver on it to adjust
fuel delivery.  It's used to adjust your fuel to arrive at the correct jet
size without pulling the carb apart and swapping jets.  Once you have the
correct jet size, you no longer need it.  The adjustment is made with a
needle valve so you won't have the range of rich-stoichiometric-lean-idle
cut-off in the cockpit.  Tom McNeilly's leaning block will go through the
entire mixture range with a traditional push/pull control.  I've been
waiting for a one for 18 mos but he says he's almost done with a batch.

Todd Archer

I meant Tom McNeilly's leaning block.

Paul Lamar